Microsoft has already made Windows free to OEMs for tablets with screens below a certain size. Making it free to everyone but without the desktop would be a logical extension of this. It gives Microsoft the tools to compete with both Android on tablets and Chrome OS on laptops, while still not cutting it out of the revenue loop entirely. Desktop-less Windows should provide Microsoft with some amount of revenue through applications bought in the Store.

To this, add a couple of levels of unlocks: one tier for regular Windows desktop features (offering parity with the feature set of Windows 8.1 today), and a second, higher tier for Windows corporate features (offering parity with Windows 8.1 Pro). These could be both persistent unlocks or periodic subscriptions. Microsoft has already had persistent operating system unlocks since Windows Vista's Anytime Upgrade feature, so none of this would be hugely different from what's gone before.

The facts and rumours do line up, but honestly - free/subscription-based Windows is right up there with a TV from Apple when it comes to long-running, always-returning but never materialising rumours.

Just look at all the android apps that were recently found to contain bitcoin miners.

To be honest, that's because Google's vetting-process sucks ass. They only use a bot to do the vetting, no humans involved, and it was already shown several years ago to be too easy to fool. AFAIK both Microsoft and Apple are much, much more involved in the process of vetting submissions.